Primates are diverse regarding morphologically and ecologically. They play significant roles in the various niches of the ecosystem. In relation to the effects on the fitness, there are six possible combinations of biological interaction between primates and other species, ranging from harmful to mutually beneficial interactions and neutral interactions, such as predator-prey interaction (i.e., herbivory, predation and parasitism), competition, amensalism, mutualism, commensalism and neutralism, which result in the diverse species interactions. Therefore biological interactions between primates and other species have been studied. There are two major advantages in the ecological research of primates. Firstly, researchers are able to clarify detailed individual behaviours and ecological processes through the direct observation of primate individuals. Secondly, researchers are able to follow the secular trends of individual growth and/or lineages of blood relations through the long-term research of identified primate troops. We need further researches in the primate-other species interaction by applying field experiments, systematic background data, research networks, new research technology, meta-analysis methods, and transdisciplinary idea.